Originally Posted by Xus
However, with both FBreader and Adilko installed (and having no problem whatsoever to read the ebooks when I browse for them from within those apps), the "Read" button reacts just the same (the message mentioned above).
What kind of books are you trying to open, Mobi, Epub? I have a Nexus 7 and when I have multiple reader apps installed opening a book via Calibre Companion (CC) allows me to choose which app to use. When opening Mobi books I get the choice of Moon+ Reader or FBReader. When opening a Epub I get a choice between Moon+ Reader, Aldiko, Cool Reader and FBReader. (Now that I finished testing it is time to remove all but Moon+Reader Pro, my reader of choice.)
Is there anything unique about your setup?
Do you have the latest version (2.4) of CC installed?
Are you connected to calibre or the calibre content server during the attempt to open a book?
You might want to try resetting your Nexus 7 by turning your device off then back on?
Sorry I couldn't be of more help.